Backup procedures for computers are well known. Backup procedures are performed in order to provide a copy of the data stored on a computer or an associated storage device, so that the data can later be restored in the event that the original data is accidentally or maliciously lost.
As those skilled in the art will appreciate, data can be accidentally lost through computer hard disk failures, power losses, fires, floods, earthquakes, and a variety of other unfortunate events. Data can be maliciously lost through erasure, viruses, tampering, and other such intentional events. There is simply no way known at the present to prevent such accidental and malicious loss of data.
However, actual harm caused by the loss of data can be mitigated with comparatively little cost and inconvenience by implementing backup procedures to prepare for this eventuality. The use of backup procedures is general far less expensive and inconvenient than the consequences of irretrievably losing the data. One of the consequences of irretrievably losing data may be the need to reconstruct the data. Reconstruction of the data is likely to be an undesirably costly and time consuming process.
Frequently, the data simply cannot be reconstructed. The original sources of the data may no longer exist or may be untraceable. Important information is often permanently lost with severe financial consequences.
Backing up data is merely the process of making an extra copy of the data, so that if the original data is lost or corrupted, the extra copy may be used in its place. This redundancy decreases the likelihood that a single incident or malicious event can make the data permanently unavailable.
Typically, the backed up data is copied to another storage device. This backup storage device typically has removable media, so that the backed up data can then be easily moved to a remote location for safe keeping. Thus, even in the event of a catastrophe, such as a fire or earthquake, at the location of the original data, the backed up data is not likely to be affected.
Various different systems for performing backups are known. Backups can be made to network attached storage (NAS) devices, storage area networks (SANs) and a variety of other storage devices including tape drives.
A NAS device is a storage device that is dedicated solely to file sharing. NAS devices typically communicate using TCP/IP over an Ethernet connection. Although multiple storage devices can be used, NAS systems frequently use a single storage device. A NAS device can add storage capacity to a server without disruption of the system. That is, since a NAS device is not an integral part of a server, there is no need to shut down the system for maintenance or upgrades when adding a NAS device. A NAS device can be located anywhere that is desired within a LAN.
A SAN is a network of shared data storage devices that communicate using Fibre Channel over a SCSI interface. Thus, a SAN has several separate storage devices. A SAN provides simplified storage management, more efficient access to stored data, scalability, and easier backup.
An advantage of backing up to a NAS device, a SAN, or some other disk based storage system rather than backing up to a tape drive is the speed of the process. Since backups can be performed much more rapidly to disk based storage system, there is less disruption to the server, as well as to the network in general, than when a backup is being made to a tape drive. Thus, it is possible to perform a backup during the day when the server is busy.
However, backups are typically transferred to tape after they are initially performed to a disk based storage system. This is desirable in order to free up storage capacity on the disk based storage system and to facilitate removal of the media to a remote location for safe keeping.
Transfer of the backed up data to tape necessitates that the data be formatted for the particular tape drive being used. Disk based storage systems, such as NAS devices, may lack the ability to format the data in this manner. Therefore a computer, such as a server, must therefore be used to effect this process. Of course, the server's resources are generally better spent performing the server's normal duties, such as serving files.
Even if the disk based storage system is capable of formatting the data for storage on the tape drive, it is not desirable to have the disk based storage system do so. Having the disk based storage system format the data undesirably reduces the availability of that system for routine data storage tasks.
Thus, although such contemporary disk based backup methods and systems have proven generally suitable for their intended purposes, they possess inherent deficiencies which detract from their overall effectiveness and desirability. The resources of a server or storage device are undesirably tied up during the process of transferring previously backed up data to from a disk based storage device to a tape drive. This inefficient use of such resources reduces the advantages of storing the data to the disk based storage system in the first place.
As such, although the prior art has recognized, to a limited extent, the problem of maximizing the availability of server and storage resources during backup processes, the proposed solutions have, to date, been ineffective in providing a satisfactory remedy. Therefore, it is desirable to provide a method and system for backing up data to a disk based storage system, such as a NAS device or a SAN, and subsequently to a tape drive, wherein the undesirable use of system resources is mitigated.